Human Adipose-Derived Mesenchymal Stem Cells for Osseous Rehabilitation of Induced Osteoradionecrosis: A Rodent Model.

Objective Human adipose-derived mesenchymal stem cells (ADSCs) were used to rehabilitate bone damaged by osteoradionecrosis (ORN) in an established animal model. Study Design Prospective animal study. Setting Academic department laboratory. Subjects and Methods After institutional review board and Institutional Animal Care and Use Committee approval, 24 athymic nude rats were divided into 5 groups: 4 groups irradiated (20 Gy) by brachytherapy catheter placed at the left hemimandible and 1 mock irradiation control (n = 4). For all groups, ORN was initiated by extraction of the central molar 1 week later. After 28 days, animals (n = 5/group) received injection at the extraction site with saline (SAL), ADSCs, platelet-rich plasma and collagen (PRP/COL), or ADSCs + PRP/COL. Rats were sacrificed 28 days later and their mandibles harvested for histopathology analysis (osteoblasts, osteoclasts, and fibrosis) and bone volume measurement using 3-dimensional micro-computed tomography. Results All but 1 rat survived the experiment period (23/24). Radiographic and histological analysis revealed 60% bone loss in the SAL group compared with the nonirradiated control. Injection of ADSCs increased jaw region bone volume by up to 36% ( P < .01). All experimental groups (ADSC, PRP/COL, and ADSC + PRP/COL) showed dramatically decreased osteoclast counts ( P < .001) while injection of PRP/COL with or without ADSCs increased osteoblasts. Increased fibrosis was observed after ADSC injection ( P < .05). Conclusion The application of human ADSCs to an induced mandibular osteoradionecrosis model in athymic rats results in increased deposition or preservation of bone, demonstrated both histologically and radiographically. This offers an encouraging possible treatment option for translational research in this difficult disease.

Long-term Treatment Outcomes for Locally Advanced Esophageal Cancer: A Single-Institution Experience.

OBJECTIVES: To determine long-term outcomes in patients with locally advanced esophageal carcinoma treated with trimodality therapy (chemoradiotherapy [CRT] and surgery, TMT) or definitive CRT. METHODS: We retrospectively identified patients with advanced esophageal carcinoma treated with curative intent at our institution between 1998 and 2004. Identified patients were separated into 3 groups: patients who received TMT, patients who received CRT, and patients who began treatment with trimodality intent but did not undergo surgery (PTMT). Local control, overall survival (OS), and distant metastasis-free survival were compared using Kaplan-Meier statistics. RESULTS: Among the 265 patients included, median follow-up was 6.4 years for surviving patients and 1.7 years for all patients. Type of esophageal cancer was adenocarcinoma in 213 patients (80%) and squamous cell carcinoma in 46 patients (17%). Treatment groups comprised 169 patients (64%) completing TMT, 46 patients medically unable to undergo surgery after neoadjuvant therapy (PTMT), and 50 (19%) who underwent CRT. Median OS was 20.5 months; actuarial 5- and 10-year OS were 27% and 12%, respectively. The TMT group had the highest 5- and 10-year OS (32% and 19%, respectively). Local control rates at 2, 5, and 10 years for all patients were 80%, 70%, and 69%, respectively. By treatment modality, 5-year local control was best (82%) for TMT, compared with 60% for CRT and 40% for PTMT groups (P<0.001). CONCLUSIONS: Patients who completed TMT had the best local control and long-term OS. In the context of TMT, surgery seemed more beneficial in patients with esophageal adenocarcinoma versus squamous cell carcinoma.

An Athymic Rat Model for Mandibular Osteoradionecrosis Allowing for Direct Translation of Regenerative Treatments.

OBJECTIVE: We aim to create a model of mandibular osteoradionecrosis in athymic rats. Athymic rats provide an immunosuppressed environment whereby human stem cells and biomaterials can be used to investigate regenerative solutions for osteoradionecrosis, bridging the gap between in vivo testing and clinical application. STUDY DESIGN: Prospective animal study. SETTING: Academic otolaryngology department laboratory. SUBJECTS AND METHODS: After Institutional Animal Care and Use Committee approval, 10 athymic nude rats were divided into 2 groups. The experimental group (n = 6) underwent irradiation (20 Gy), while the control group (n = 4) underwent sham irradiation catheter placement only. All 10 rats underwent extraction of the second mandibular molar 7 days later. The rats were sacrificed 28 days after dental extraction, and their mandibles were harvested. The mandibles were examined with histologic analysis and bone volume analysis based on 3-dimensional micro-computed tomography. RESULTS: All 10 rats survived the experiment period. Radiographic and histologic analysis revealed decreased bone formation in the experimental group compared with the control group. Jaw region volume ratio was 0.83 for the experimental group versus 0.97 in the control group (P = .003). The region-of-interest volume ratio was 0.75 in the experimental group and 0.97 in the control group (P = .005). Histologically, there were increased osteoclasts (P = .02) and decreased osteoblasts (P = .001) as well as increased fibrosis in the experimental group versus the control group. CONCLUSION: Mandibular osteoradionecrosis can be effectively and reproducibly produced in an athymic rat model. This will allow further research to study regenerative medicine in an athymic rat model.

Design and characterization of an economical (192)Ir hemi-brain small animal irradiator.

PURPOSE: To describe the design and dosimetric characterization of a simple and economical small animal irradiator. MATERIALS AND METHODS: A high dose rate (HDR) (192)Ir brachytherapy source from a commercially available afterloader was used with a 1.3 cm thick tungsten collimator to provide sharp beam penumbra suitable for hemi-brain irradiation of mice. The unit was equipped with continuous gas anesthesia to allow robust animal immobilization. Dosimetric characterization of the device was performed with Gafchromic film measurements. RESULTS: The tungsten collimator provided a sharp penumbra suitable for hemi-brain irradiation, and dose rates on the order of 200 cGy/minute were achieved. The sharpness of the penumbra attainable with this device compares favorably to those measured experimentally for 6 MV photons, and 6 and 20 MeV electron beams from a linear accelerator, and was comparable to those measured for a 300 kVp orthovoltage beam and a Monte Carlo simulated 90 MeV proton beam. CONCLUSIONS: Due to its simplicity and low cost, the apparatus described is an attractive alternative for small animal irradiation experiments requiring steep dose gradients.